Question

Heat is added to a 200.-gram sample of H2O(s) to melt the sample at 0°C. Then the resulting H2O (image) is heated to a final temperature of 65°C. Determine the total amount of heat required to completely melt the sample.

Answer 1

You are given 200 grams of H2O(s) at an initial temperature of 0°C. you are also given the final temperature of water after heating at 65°C. You are required to get the total amount of heat to melt the sample. The specific heat capacity, cp, of water is 4.186 J/g-°C. Let us say that T1 = 0°C and T2 = 65°C. The equation for heat, Q, is  

Q = m(cp)(T2-T1)
Q = 200g(4.186 J/g-°C )(65°C - 0°C)
Q = 54,418J

Answer 2

Answer: 54.418 kJ amount of heat required to completely melt the sample.

Explanation:

Mass of water = 200 g

Initial temperature of the water = 0°C

Final  temperature of the water = 65°C

Temperature change =$\Delta T=65^oC-0^oC=65^oC$

Specific heat capacity = $4.186J/g^oC$

$Q=mC\Delta T=200 g\times 4.186J/g^oC\times 65^oC$

$Q=54,418 J=54.418 kJ$  (1 kJ = 1000J)

54.418 kJ amount of heat required to completely melt the sample.